The LED sensor in the LoadLock that tells the system
that a wafer is present in the pocket of the load arm,
is getting weak. I've optimizd the adjustment, but cannot
get any more sensitivity. We need to get a new sensor.
Meanwhile, if the system does not recognize your wafer
on the load arm, mount your sampe on the backside
of the carrier wafer, so that the polished side is facing
down.